The spontaneous combustion characteristics of Turkish lignite and correlation of the self-heating process with the actual fire
Fires due to self-heating of coal have been a real problem since the beginning of mining. In order to minimize the harmful effect of fires caused by spontaneous combustion (sponcom), the tendency of coal for sponcom should be analyzed in detail. This paper presents the results of such research, which had two objectives: firstly, to determine the spontaneous combustion characteristics of lignites of all underground (u/g) mines of Turkish Coal Enterprises (TKÍ) in the laboratory; and secondly, to use these self-heating characteristics to predict the stage and progress of actual mine fires. Representative samples of 16 different lignite seams were prepared for tests in the laboratory. Crossing-point temperature and adiabatic oxidation methods were utilized to characterize the spontaneuos combustion risks. During the experiment, time and temperature were measured, and released gases were continously recorded. Sponcom results obtained by both methods were in close agreement with each other, and it was determined that Turkish lignites are susceptible to spontaneous combustion with medium to high risk. All the information obtained from the laboratory tests was utilized to predict the progress of an actual mine fire. Finally, a fairly good correlation was established between the spontaneous combustion test results and an actual mine fire caused by self-heating. Observations of CO emissions during an actual mine fire, which occurred in the Middle Anatolian Lignite mine, supported the suggested prediction method. This prediction method is currently being used in all TKÍ’s u/g mines.
Spontaneous combustion, Mine fires, Crossing-point temperature, Adiabatic oxidation, Turkish lignites.